A number of neutron radiotherapy trials are on going in the United States and in other countries. The results have been encouraging enough to warrant effort towards a full understanding of the neutron interactions with tissue-resident elements, and the optimization of this modality. The main purpose of this work is to measure the fundamental quantities (cross sections) for the production of charged particles as a function of outgoing particle type (hydrogen, helium, etc., ions) and energy for neutron beams of various energies incident on tissue resident elements. These measurements will allow the calculation of kerma, LET, and dose in tissue of any composition, and for any neutron energy spectrum. The calculations will be made by, and in collaboration with, the Naval Research Laboratory theoretical group. A charged particle detection and data acquisition system has been developed to detect the ions in the energy range 3 to 60 MeV which are produced by monoenergetic neutrons of various energies in the range 20 to 60 MeV. BIBLIOGRAPHIC REFERENCES: A Detection System for Neutron-Induced Charged Particles of 3 to 60 MeV. J.L. Romero, T.S. Subramanian, F.P. Brady, N.S.P. King, and J.F. Harrison, Bulletin of the American Physical Society 24 (1977). 12C(n,p)12B Reaction at 45, 56.3 and 64 MeV, T.S. Subramanian, F.P. Brady, J. Romero, J.L. Ullmann and N.S.P. King, Bulletin of the American Physical Society 24 (1977).